Strip rolling method



Marh 9, 1965 'r. A. FOX 3,172,315

STRIP ROLLING METHOD Filed July 10. 1961 2 Sheets-Sheet l INVENTOR Thomas A. Fox

March 9, 1965 'r. A. Fox 3,172,315

STRIP ROLLINQMETHOD Filed July 10, 1961 2 Sheets -Sheet 2 INVENTOR Thomas A. Fox

United States Patent 3,172,315 STRIP ROLLING MEI'HOD Thomas A. Fox, P0. Box 314, Poland, Ohio Filed July 10, 1961, Ser. No. 122,939 6 Claims. (Cl. 8060) This invention relates to strip rolling apparatus methods and particularly to methods for cold rolling strip and sheet to controlled gauge. This invention is a continuation in part of my copending application Serial No. 97,308, filed March 21, 1961.

It is now a well recognized fact that metal strip or sheet can most effectively be rolled by the use of small work rolls backed up by one or more back-up rolls of large diameter. This is so because of the considerable variation in the amount of work involved in moving the rolls depending upon the working arc of the roll.

One of the most important problems facing manufacturers of metal strip is the problem of gauge control, i.e., control of the thickness of the strip from end to end and side to side. This problem has been one of long standing and many attempts have been made to solve it. These attempts have encompassed apparatus for applying and varying the roll pressure, variations in roll design, multiple roll arrangements, etc. These expedients have, however, been expensive, unsatisfactory and failed to completely solve the problem.

I have invented a strip rolling method which overcomes these problems of gauge control. I provide a method which generally stated comprises the steps of passing a strip through between a pair of small diameter work rolls for metal reduction, with a larger diameter back-up roll for each work roll, one pair of said work rolls or said back-up rolls being driven, and controlling the relative position of the pair of said work rolls and back-up rolls to provide a load variation in one direction or the other on the driven rolls. This action may be created by power means and act as an additive or subtractive load on the main driving force of reduction. The resultant of such power means on the undriven roll is to cause the axis of each work roll to move from one side to the other of the vertical axis of the back-up rolls or to a position directly on such vertical axis dependent upon the forces of rolling and the force exertedly the power means thus varying the gauge of the strip. Preferably the power means is a hydraulic or electric motor or a brake. In a preferred form of my invention I provide a sensing means adjacent the strip adapted to signal a change in strip gauge from a null position to a control means for the power means. The power means may alternatively be manually operated with the signal being visible on a dial or like means visible to the operator. The sensing means may be in the form of load cells, the Shefiield air gauge, a movable rheostat arm, or may be actuated through variations of load on the drive means.

In the foregoing general statement, I have set out certain objects, advantages and purposes of my invention. Other objects, purposes and advantages of my invention will be apparent from a consideration of the following description and the accompanying drawings in which:

FIGURE 1 is a vertical side elevational view of a 4 high rolling mill in accordance with my invention;

FIGURE 2 is a diagrammatic view of a rolling mill arrangement according to a preferred embodiment of my invention;

FIGURE 3 is a diagrammatic view of a rolling mill arrangement according to a second embodiment of my invention;

FIGURE 4 is a diagrammatic view of a rolling mill arrangement according to a third embodiment;

FIGURE 5 is a diagrammatic view of a rolling mill arrangement according to a third embodiment of my invention;

FIGURE 6A is a schematic exaggerated front elevation of a mill according to FIGURES 1 and 2;

FIGURE 6B is a schematic exaggerated front elevation of the mill of FIGURE 6A in a different position; and

FIGURE 7 is a schematic illustration of the embodiment of FIGURE 1 with a control system in schematic form.

Referring to the drawings I have illustrated a mill housing 10 of generally conventional design. Mounted in housing It) are a pair of work rolls 11, journaled in bearing chocks 12 in usual manner, and backed up by back-up rolls 13 as is the case in most 4 high mills. The back-up rolls 13 are journaled in chocks 14 in the housing 10 and are driven by drive motors 15 through couplings 16 of usual design.

The work rolls 11 are provided with drive motors 17 and couplings 18 to the roll necks. The work roll axes are in the same vertical plane as the back-up roll axes so that any lateral bowing movement will carry a portion of the Work roll out of this plane and the con tact of the work roll and back-up roll will tend to be in an arcuate shape. The effect of this lateral displacement is readily detected by visual observation or by conventional detecting or sensing means measuring thickness variations of the strip or actual deflection of the work rolls 11.

A take up reel drum 22 of usual design is used to take up the finished strip. This reel is driven by a conversion motor drive 23. Similarly a conventional pay out reel 24 is provided on the feed side of the mill. This reel 24 may be provided with a drive or brake in conventional manner.

In the form illustrated in FIGURES 1 and 2, I have illustrated a manually operable device. The operation of this device is as follows. The strip passing from pay out reel 24 through work rolls 11 onto take up reel 22 is reduced by the action of the work rolls which are frictionally driven through the back-up rolls 13. These rolls are set to give a particular desired gauge. If the strip begins to show variations in thickness, the operator, seeing this change on sensing dial energized by load cells 100a energizes drive motors 17 to rotate the work rolls 11 in a direction opposite or with the frictional drive of the back-up rolls. In FIGURE 2 the back-up rolls would be rotating in clockwise direction and urging the work rolls in the counter clockwise direction. With an increase or decrease in strip thickness, the drive motors 17 would react on the work rolls tending to carry them backward or forward beneath the back-up rolls, as the operator desired, correcting for existing gauge errors. This would bring the gauge back toward normal level.

In the embodiment of FIGURE 7 I have illustrated the same drive arrangement as FIGURE 2 but with automatic controls. Load cells 19 are mounted above the strip pass line 20 with feeler arms 21 in contact with the face of the strip. The load cells are arranged to give a signal in one direction or the other depending upon the direction of gauge change resulting from displacement of the work rolls 11. Motors 17 are energized to rotate in one direction or the other depending upon the displacement of rolls 11. The motors 17 are energized by current from the amplifier motor controller 17b which is actuated by the current flow from the load cells 19.

The operation of the device of FIGURE 7 is as follows. The strip passing from pay out reel 24a through between work rolls 11a onto take-up reel 22:: is reduced by the action of the work rolls which are frictionally driven through the back-up rolls 13a. If the strip center to edge thickness changes, this is noted by the feeler arms 21 which move and energize the load cells 19 which will energize drive motors 17a to rotate the work rolls in a direction opposite 'to the frictional drive of the back-up rolls. In this example with the strip moving toward the right in FIGURE 7 the back-up rolls would be rotating in the clockwise direction and urging the work rolls to rotate in counterclockwise direction. With lateral displac ment to the left and an increase in gauge, as predicated in this example, the drive motor 17a would urge the work rolls in the clockwise direction tending to carry them back beneath the back-up rolls.

If on the other hand the take-up reel is exerting a greater pressure on the work rolls and urging them toward the right then the work roll drive would cause them to increase their rotation in the counterclockwise rotation thus supplementary the back-up roll frictional drive. 7

A brake arrangement, such as a generator, or any other known form of retarding device might be used for limited gauge control. Such an arrangement is shown in FIG- URE 3 where a brake 17b is substituted for motor 17 of FIGURE 2.

In FIGURE 4 I have illustrated another form of my invention in which the work rolls 40 are driven by main drive motors 41 and the back-up rolls 42 are driven by main drive motors 43 capable of retarding or driving the back-up rolls to cause the driven work rolls to be moved with respect to the back-up roll to vary the strip gauge.

In the embodiment of FIGURE 4 the driven rotation of work rolls 40 in counterclockwise direction by motor 41 will cause them to move to the left while frictionally rotating back-up rolls 42 in the clockwise direction. If the counterclockwise rotation is applied to the back-up rolls 42 by motors 43, the work rolls 40 will be forced to re turn to their normal or null position beneath the back-up rolls.

A braking arrangement similar to that of FIGURE 3 could be substituted for theretarding motors 43 on backup rolls 42.

In FIGURE 5 I have illustrated still another embodiment in which work rolls are backed up by back-up.

rolls 51 driven by motors 52. Each end of each work roll 50 is connected to a drive motor 53 through a drive shaft 54. The operation of this arrangement is identical with that of FIGURE 2, however, the use of motors 53 on each end of the work rolls produces greater uniformity of action on small diameter work rolls.

In FIGURE 6A I have illustrated schematically an exaggerated front elevation of work rolls and back-up rolls with strip therebetween with large center to edge thickness ratio. In 6B I have shown the same mill with the work rolls driven opposite to the back-up rolls to bring them into the plane through the axes of the back-up rolls. 7

While I have illustrated and described certain present preferred embodiments of my invention it will be understood that this invention may be otherwise embodied within the scope of the following claims.

I claim:

1. A method of gauge control for rolling strip material, comprising the steps of passing the strip to be rolled between a pair of small diameter work rolls adapted to provide a working pass for said strip material, backing said work rolls with a large diameter back-up roll for each work roll, driving one pair of'said rolls in a direction to move the strip through between the work rolls, and varying the speed of the undriven pair of said rolls to cause the work roll centers to move transversely of the plane through the back-up roll axes to vary the gap between the work roll surfaces. V

2. A method of gauge control forrolling strip'material comprising the steps of passing the strip to be rolled between a pair of small diameter work rolls adapted to provide a working pass for said strip material, backing said Work rolls with a large diameter back-up roll for each work roll, driving one pair of said rolls in a direction to move the strip through between the Work rolls and driving the other pair of said rolls to cause the work roll centers to move transversely of the plane through the back-up roll axes to vary the gap between the work roll surfaces.

3. A method of gauge control for rolling strip material, comprising the steps of passing the strip to be rolled between a pair of small diameter work rolls adapted to provide a working pass for said strip material, backing said Work rolls with a large diameter back-up roll for each work roll, driving one pair of said rolls in a direction to move the strip through between the work rolls and braking the speed of the undriven pair of said rolls to cause the work roll centers to move transversely of the plane through the back-up roll axes to vary the gap between the work roll surfaces.

4. A method of gauge control for rolling strip material, comprising the steps of passing the stripto be rolled between a pair of small diameter work rolls adapted to provide a working pass for said strip material, backing said work rolls with a large diameter back-up roll for each work roll, driving the pair of back-up rolls in a direction to move the strip through between the work rolls and controlling the speed of the pair of said work rolls with respect to the speed of the back-up rolls to cause the work roll centers to move transversely of the plane through the back-up roll axes to vary the gap between the work roll surfaces.

5. A method of gauge control for rolling strip material,

comprising the steps of passing the strip to be rolled between a pair of small diameter work rolls adapted to provide a working pass for said strip material, backing said work rolls with a large diameter back-up roll for each work roll, driving said back-up rolls in a direction to move the strip through between the work rolls, sensing variations of the center to edge thickness of the strip passing between the work rolls and controlling the speed of the undriven pair of said rolls to cause the work roll centers to move transversely of the plane through the back-up roll axes to vary the gap between the work roll surfaces.

6. A method of gauge control for rolling strip material, comprising the steps of passing the strip to be rolled between a pair of small diameter work rolls adapted to provide a working pass for said strip material, backing said work rolls with a large diameter back-up roll for each work roll, driving the pair of back-up rolls in a direction to move the strip through between the work rolls, measuring the variation in the center to edge thickness of the strip leaving the work rolls and rotating the said pair of work rolls to cause the work roll centers to move transversely of the plane through the back-up roll axes to vary the gap between the work roll surfaces.

References Cited by the Examiner UNITED STATES PATENTS 1,793,114 2/31 Minton 100-163 2,601,792 7/52 Dahlstrom -38 2,792,730 5/57 Cozzo 80-562 3,006,225 10/61 Mamas 80-562 3,018,676 1/62 Polakowski 80-321 3,044,392 7/62 Minarik -172 FOREIGN PATENTS 7,992 5/11 Great Britain.

WILLIAM J. STEPHENSON, Primary Examiner.

CHARLES W. LANI-IAM, WILLIAM W. DYER, JR.,

Examiners. 

1. A METHOD OF GAUGE CONTROL FOR ROLLING STRIP MATERIAL, COMPRISING THE STEPS OF PASSING THE STRIP TO BE ROLLED BETWEEN A PAIR OF SMALL DIAMETER WORK ROLLS ADAPTED TO PROVIDE A WORKING PASS FOR SAID STRIP MATERIAL, BACKING SAID WORK ROLLS WITH A LARGE DIAMETER BACK-UP ROLL FOR EACH WORK ROLL, DRIVING ONE PAIR OF SAID ROLLS IN A DIRECTION TO MOVE THE STRIP THROUGH BETWEEN THE WORK ROLLS, AND VARYING THE SPEED OF THE UNDRIVEN PAIR OF SAID ROLLS TO CAUSE THE WORK ROLL CENTERS TO MOVE TRANSVERSELY OF THE PLANE THROUGH THE BACK-UP ROLL AXES TO VARY THE GAP BETWEEN THE WORK ROLL SURFACES. 